Water cooled burner and feedstock injection assembly for carbon blackreactor

ABSTRACT

A burner and feedstock injection assembly for a carbon black reactor having a cooling-water jacket surrounding the center air pupe (which surrounds the center feedstock pipe). Means are included within the jacket for imparting a whirling motion to the water as it circulates through the portion of the jacket which is subjected to maximum heat of fuel combustion. Preferably, the jacket includes an expansion joint mounted outside the reactor toward the upstream end of the assembly.

United States Patent [191 Matthews et al.

[ June 26, 1973 WATER-COOLED BURNER AND 3,236,281 2/1966 Bain et al l22/6.5 X FEEDSTOCK INJECTON ASSEMBLY FOR 3,559,623 2/1971 DeCamps 122/65 CARBON BLACK REACTOR [75] Inventors: Roy S. Matthews, Sunray; Billy E- Primary Examiner-Kenneth W. Sprague Willis, Houston, both of AttorneyJerry B. Peterson et al. [73] Assignee: Continental Carbon Company,

Houston, Tex.

[22] Filed: Sept. 29, 1971 [57] ABSTRACT 21 A l. N 184934 1 pp 0 A burner and feedstock injection assembly for a carbon Related pp Data black reactor having a cooling-water jacket surround- [63] Continuation-impart of Ser. No. 59,962, Jul 31, ing the center air pupe (which surrounds the center 1970. feedstock pipe). Means are included within the jacket for imparting a whirling motion to the water as it circu- [52] U.S. Cl. 122/6.5 lates through the portion of the jacket which is sub- [51] Int. Cl. F22b 37/00 jected to maximum heat of fuel combustion. Prefera- [58] Field of Search 122/65, 6.6 bly, the jacket includes an expansion joint mounted outside the reactor toward the upstream end of the as- [56] References Cited sembly.

UNITED STATES PATENTS 2,632,503 3/1953 Bailey 122/65 4 Claims, 3 Drawing Figures FUEL COMBUSTION l3 AIR CENTER AIR I H 4 file FEEDSTOCK 1 f 1: L g .15 2 3 COMBUSTION AIR PATENTED JUN 2 6 I975 $0.1m In m zofrmnmzou INVENTORS ROY s. MATTHEWS BILLY E. WILLIS BY 2 :2 mwhzuo ATTORNEY WATER-COOLED BURNER AND FEEDSTOCK INJECTION ASSEMBLY FOR CARBON BLACK REACTOR CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of Ser. No. 59,962, filed July 31, 1970.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the production of carbon black by the injection of a suitable hydrocarbon feedstock into an elongate reaction or combustion chamber containing high-temperature flames and gases, and

more particularly to a novel watercooled burner and feedstock injection assembly for burning a gaseous or liquid hydrocarbon as fuel to provide the heat necessary for the pyrolysis of the feedstock to form carbon black.

2. Description of the Prior Art This invention is an improvement over the assembly of U.S. Pat. No. 3,443,761 and is designed to minimize or eliminate damage to the feedstock nozzle and the axial air pipe which results from overheating when the feedstock and the axial air pipe of that patent are shoved into the reactor (for reasons which will be explained hereinafter).

Applicants do not claim that water-cooled carbon black burners are novel per se. For example, U.S. Pat. Nos. 2,659,662, 2,895,804, 3,003,854 and 3,490,869 show water-cooled carbon black burners; however, it will be noted that as to all of these patents the burner design and method of water cooling is vastly different from applicants invention.

SUMMARY OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view, partly in section, illustrating the preferred embodiment of the burner and feedstock injection assembly;

FIG. 2 is a longitudinal view, partly in section, of one form of a suitable carbon black reactor including the preferred burner and feedstock assembly;

FIG. 3 is a longitudinal view, partly in section, showing another suitable form of a carbon black reactor including the preferred burner and feedstock injection assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, burner and feedstock injection assembly 1 will first be described. The feedstock line is center pipe 2 which is slideably mounted within axial pipe 3 and sealed therefrom by means of suitable packing glands included within closure member 4. The

downstream end of center pipe 2 is provided with a I suitable spray nozzle 5, which can be any conventional commercially available nozzle.

The upstream end of axial pipe 3 may be provided with a pipe 3a for introduction of air into the annulus between the center pipe and the axial pipe, for the pur pose of assuring that feedstock does not pass into the annulus.

The tip of nozzle 5 terminates in approximate flush relationship with axial pipe 3.

Pipe 6, axial pipe 3, tubular member 7 and end plate 8 define a jacket through which a cooling medium can flow, preferably entering through pipe 9 and exiting through pipe 10, but possibly entering through pipe 10 and exiting through pipe 9.

The annulus between tubular member or pipe 11 and pipe 12 provides a passageway for a hydrocarbon fuel such as natural gas, which is introduced through pipe 13 and enters the reactor through aperture 14 and makes contact with combustion air as shown.

A spiral baffle 15 is included to impart a whirling motion to the cooling medium in order to provide better heat exchange to prevent the formation of damaging hot spots. Preferably, this baffle is positioned and designed as shown in order that it also can function as a spacer. Although it is preferable to position the baffle 15 between pipe 6 and tubular member 7, as shown, it would be possible to position the baffle between axial pipe 3 and tubular member 7.

Expansion joints 16 and 17 are preferably included to allow for expansion and contraction resulting from temperature changes.

Circular disc 18 is rigidly affixed to pipes 11 and 12. The primary purpose of the disc 18 is to prevent blowout of the flame under operating conditions.

Pipe 6 is slideably mounted within the assembly by means of closure member 19 so that the entire subassembly comprising center pipe 2 and the jacket may be (and normally is) extended into the reactor in order that feedstock nozzle 5 can be positioned within thereactor at a predetermined point downstream of disc 18. Such adjustment of the position of the feedstock injection nozzle within the reactor makes it possible to optimize the primary reinforcing quality of carbon black as expressed by tinting strength and treadwear resistance as well as to adjust the structure properties. Within limits, the further the feedstock nozzle is extended into the reactor of FIG. 2, the higher the tinting strength and treadwear index, and the lower the structure of the black. The jacket for coolingmedium allows greater flexibility in adjusting these properties, because the feedstock nozzle can be extended further into the combustion zone without burning up the axial pipe 3 and nozzle 5.

FIGS. 2 and 3 show the preferable positioning of the burner and feedstock injection assembly in the upstream end of an elongate tubular carbon black reactor 20. Preferably, the assembly is slideably mounted in the reactor so that the positioning of the assembly within the reactor can be varied in order to optimize the combustion pattern for any given reactor configuration and any total charge of fuel and oxygen-containing gas.

Although thespecific design of the elongate tubular carbon black reactor is not critical to the practice of this invention, we prefer the design shown in FIG. 2, which is designed for the production of tread grades of black; however, FIG. 3, which is designed for the production of carcass grades, could also be used.

Referring to FIG. 2, preheated air passes through annulus 21 formed by shell 22 and inner tube 23. Portions of the air enter the interior of the reactor through louvers 24 in combustion air device 25. A portion of the combustion air also enters the reactor through annular opening 26. The downstream end of the reactor can be of any suitable design, as for example FIG. 1 of U.S. Pat. No. 3,256,065 or FIG. 1 of U.S. Pat. No. 3,256,066.

The preheated combustion air enters the reactor of FIG. 3 as shown. The downstream end of the reactor of FIG. 3 can be of any convenient design, as for example FIG. 1 of U.S. Pat. No. 2,976,127.

Although we have shown and described the invention as including means for using a gaseous fuel, it will be readily apparent to those skilled in the art that different fuels and/or means for introduction of fuel could be used. For example, the fuel oil burner and feedstock injection assembly of U.S. Pat. application Ser. No.

59,961, filed July 31, 1970 by Burton F. Latham and William B. Crull could be used in combination with the jacketed subassembly of this invention.

With the subassembly (center pipe 2 plus the jacket) pulled back into the burner as shown in FIG. 1, water cooling is not essential. As the subassembly is pushed into the reactor, circulation of cooling water becomes increasingly important and the required volume of water increases.

EXAMPLE 1 Table I below lists typical operating conditions which have been satisfactorily employed for pilot-plant operations of extended duration while using the burner'and feedstock injection assembly of FIG. 1 in a reactor substantially as shown in FIG. 2. The cooling medium used was water, which was passed through an automobile radiator in order to cool it for recirculation to the jacket.

Natural gas was used as fuel at air-to-gas ratios of about 14.5 and total combustion air rates of about 150,000 standard cubic feet per hour. The feedstock was a con- Note: In runs A and B, water was sprayed on the radiator to improve the cooling of the water from the jacket prior to recirculation.

TABLE III [SAF-HM Run No. A B C D Extension Length,

Inches 38 26 14 Coolant Temp., F.

Inlet 185 153 I59 I26 Outlet 202 167 167 131 Coolant Circulation Rate, GPM 39 39 39 39 Coolant Inlet Pressure,

psi 75 73 73 73 Atmospheric Temp, F. 98 98 90 87 Feedstock Oil Rate,

GPM at F. 182.6 194.9 189.7 179.0 Feedstock Additive, ppm potassium None 5.0 2.4 15.0 Iodine No. 119.5 123.5 124.5 123.5 DBP Absorption 112.6 115.3 116.4 114.2

Note: In runs A and B, water was sprayed on the radiator to improve the cooling of the water from the jacket prior to recirculation.

EXAMPLE 3 Table IV below lists operating conditions which have been employed for commercial production of I-IAF carbon black while using the burner and feedstock injection assembly of FIG. 1 in a reactor substantially as shown in FIG. 2. Water was used as the cooling medium at pressures of about 4555 psi, inlet temperatures of about 120-125 F. and outlet temperatures of Run No. 1 2 3 4 5 I 6 7 8 9 10 Grade HAF HAF I-IAF HAF-HS HAF-HS SAF SAF SAF ISAF ISAF Extension length, inches 22 36 42 16 34 29 40 42 20 40 Coolant temp, "F. inlet 109 190 137 184 I08 194 Outlet 135 204 247 140 200 142 224 240 1 18 203 Coolant circulation rate,

gallons per min. 12.0 12.1 11.1 12.0 12.0 Coolant pressure, psi 32 38 49 35 68 70 33 38 70. Atmospheric temp, F. 55 72 70 87 98 95 52 55 45 93 Iodine number 89 68 91 140.1 146 1 l4 1 16.3 122.0 D81 1238 122.4 122.3 1539 121.3 113.4 116 116.6 125.4 113.0

1 Distance from disc 18 to tip of nozzle 5.

ventional carbon black oil consisting of a highlyaromatic thermal tar.

EXAMPLE 2 about 140145 F. A heat exchanger was used to cool the water for recirculation to the jacket. Natural gas was used as fuel at air-to-gas ratios of about 15 and at 50 combustion air rates of about 180,000 standard cubic feet per hour. The feedstock was a conventional carbon black oil consisting of a highly-aromatic thermal tar.

TABLE IV Run No.' 1 2 3 4 5 6 7 65 Extension Length,

Inches 24 28 32 36 4O 44 48 Feedstock Oil Rate,

GPH 311 304 302 296 296 291 289 Iodine No.01

Loose Black Without water cooling, the nozzle 5 and the end of axial pipe 3 will burn up in a matter of hours or even minutes if the extension length is greater that about inches. Using the water-cooled jacket, operations can be extended almost indefinitely using extension lengths as shown in the Tables above.

While we have thus described the preferred embodiments of the present invention, many variations will be suggested to those skilled in the art. The foregoing description and examples should therefore not be considered limitative; and all such variations and modifications as are in accord with the principles described are meant to fall within the scope of the appended claims.

Having thus described our invention, we claim:

1. In a combination of a burner and feedstock injection assembly concentrically disposed within the upstream end of an elongate, substantially tubular carbon black reactor; said assembly including a center pipe for introduction of feedstock into the reactor; means defining the outer portion of the assembly for introducing fuel into said reactor, in a pattern surrounding the assembly in the vicinity of the downstream end of the center pipe; and means for introducing combustion air into the reactor; the improvement comprising:

a double-walled circular jacket surrounding the center pipe, the downstream end of said jacket being sealed from the reactor at a point approximately flush with the downstream end of the center pipe;

a tubular member inserted within the jacket to a point immediately upstream of the sealed end of the jacket;

a conduit for introducing or removing a cooling medium into the outer portion of the jacket between said tubular member and the outer wall of the jacket;

a conduit for removing or introducing said cooling medium from the inner portion of the jacket; and

whirling means inserted within said jacket for imparting a whirling motion to the cooling medium.

2. The combination of claim 1 in which the center pipe-jacket subassembly is slideably mounted within the assembly.

3. The combination of claim 2 in which said whirling means comprises a spiral baffle inserted in the outer portion of the jacket, said baffle being designed and sized so as to act additionally to space the tubular member within the jacket.

4. The combination of claim 3 in which the jacket additionally includes an expansion joint mounted outside the reactor on the upstream end of the jacket. 

1. In a combination of a burner and feedstock injection assembly concentrically disposed within the upstream end of an elongate, substantially tubular carbon black reactor; said assembly including a center pipe for introduction of feedstock into the reactor; means defining the outer portion of the assembly for introducing fuel into said reactor in a pattern surrounding the assembly in the vicinity of the downstream end of the center pipe; and means for introducing combustion air into the reactor; the improvement comprising: a double-walled circular jacket surrounding the center pipe, the downstream end of said jacket being sealed from the reactor at a point approximately flush with the downstream end of the center pipe; a tubular member inserted within the jacket to a point immediately upstream of the sealed end of the jacket; a conduit for introducing or removing a cooling medium into the outer portion of the jacket between said tubular member and the outer wall of the jacket; a conduit for removing or introducing said cooling medium from the inner portion of the jacket; and whirling means inserted within said jacket for imparting a whirling motion to the cooling medium.
 2. The combination of claim 1 in which the center pipe-jacket subassembly is slideably mounted within the assembly.
 3. The combination of claim 2 in which said whirling means comprises a spiral baffle inserted in the outer portion of the jacket, said baffle being designed and sized so as to act additionally to space the tubular member within the jacket.
 4. The combination of claim 3 in which the jacket additionally includes an expansion joint mounted outside the reactor on the upstream end of the jacket. 